Consumer and industry demands for more functions, lower cost, and smaller form factors have increased use of integrated circuits. Integrated circuits today are used in very small systems, such as cell phones, music players, and cameras, to very large systems, such as cars, airplanes, and industrial controls. Across virtually all applications, there continues to be demand for reducing the size and increasing performance of the devices. The intense demand is no more visible than in portable electronics that have become so ubiquitous.
Smaller integrated circuit devices require a smaller package, which both encases the circuit and provides electrical interconnection to external circuitry. A leadframe is one common means of electrical interconnection. The leadframe is formed from electrically conductive material, which is formed into leads. The lead ends close to the integrated circuit device connect to the integrated circuit device by thin bond wires. The lead ends opposite the integrated circuit device are electrically connected to external circuitry such as a printed circuit board.
To protect the integrated circuit device from moisture and mechanical damage, the lead ends close to the integrated circuits and the integrated circuit device are encapsulated. Encapsulation may be accomplished by a molding compound, which surrounds both the lead ends close the integrated circuits and the integrated circuit device. Alternatively, a separate base and cover can be used to form a package. When the base and cover are attached together, the lead ends close to the integrated circuits and integrated circuit device are encapsulated within the package. Manufacturing the package includes many processes that create destructive pressure on ever shrinking dimensions.
As the demand for smaller electronic devices grows, manufacturers are seeking ways to reduce the size of the packaged integrated circuits. To meet these needs, packaging technologies are shifting towards smaller footprints with higher numbers of leads. The leads are continually shrinking in size and spacing or lead gaps. With fine pitch configurations, the lead-to-lead gap will be reduced further. This will cause the lead plating to be susceptible to shorting during the processing particularly when the package is clamped. As lead pitch is reduced, strength of the leads is also reduced. Accordingly there is a possibility that the leads are deformed, having a direct effect on the reliability of the semiconductor device.
Small form factor packages or chip scale packages, such as bump chip carriers, land grid arrays, no-lead or leadless packages are particularly susceptible to narrow lead-to-lead gaps as well as reduced strength leads. Higher numbers of leads and smaller sizes have made lead formation and encapsulation extremely difficult. Many of the processing steps may deform the fragile leads resulting in missing, hard to reach or shorted connections. The missing, hard to reach or shorted connections typically render the integrated circuit device useless.
In many configurations of multi row leadless package, the multi row leads are exposed on a top side of a flange area of the leads, due to the etching method for fabrication. A plating covers the top flange area due to multi row leads that are exposed during a plating process. With a fine pitch configuration, the lead-to-lead gap will be reduced further. This in turn will cause the solder plating to be more susceptible to shorting during a singulation process when the flange area is clamped. The shorting caused by the plating of the top flange and the reduce lead-to-lead gap resulting in useless integrated circuit device, reduces performance, functions and manufacturing yields, thereby increasing costs, complexity and throughput.
Thus, a need still remains for an integrated circuit leadless package system to provide improved reliability and manufacturing yield. In view of the increasing demand for improved density of integrated circuits and particularly portable electronic products, it is increasingly critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.